Patent GB-578156-A (GB)
Title: Process of producing a felt-like product and the products so produced
IPC: D04H1/54
Filed: 1943-08-13
Abstract: 578,156. Fabrics composed of agglutinated fibres. SYLVANIA INDUSTRIAL CORPORATION. Aug. 13, 1943, No. 13113. Convention date, Aug. 15, 1942. [Class 140] Felt-like materials are made by mixing substantially unstretched thermoplastic fibres which become tacky at or below 180‹F. with textile fibres which do not become tacky at 180‹F., forming the mixture into a layer, and heating the layer to a temperature at which the thermoplastic fibres become adhesive to bind the fibres in the product while the remaining fibres remain unaffected. Unstretched fibres are those which have not been stretched beyond 69 per cent. during manufacture. The fibres that do not become tacky at 180‹F. may be cotton, flax, jute, kapok, silk, cellulose hydrate, cellulose derivatives, natural or synthetic rubber, synthetic resins, alginic acid, gelatin, casein, spunglass, asbestos, or mineral wool. The thermoplastic fibres may be formed of plasticized cellulose acetate or ethyl cellulose, chlorinated rubber, polymers of organic compounds such as coumarone, indene, furfural, unsaturated aldehydes and ketones, vinyl compounds including vinyl acetate, vinyl chloride, acrylic acid, methyl methacrylate, and vinylidene chloride, butadiene, chloroprene, isobutylene, and also olefine polysulphide synthetic rubber, and synthetic linear polymers from dicarboxylic acids and diamines. Copolymers of vinyl halide with acrylic acid or vinyl acetate, 'and mixtures of thermoplastic materials may also be used, e.g., a mixture of a vinyl resin with acrylic acid or methacrylate resins, of olefine polysulphide with phenol aldehyde resin, of cellulose derivatives and resins, e.g., cellulose nitrate with an oil-soluble phenol-aldehyde resin, cellulose acetate and polyvinyl acetate or polymethyl methacrylate, a cellulose ether and a vinyl resin. The softening point of the thermoplastic fibres may be raised after the felt has been made either by extraction of a plasticizer from the fibres by means of a solvent therefor, or by heating to convert an initially fusible thermosetting resin to the infusible state. The fibres may be made by extrusion or by spraying a melt or solution of the thermoplastic material into a gaseous atmosphere as described in Specification 577,534. Suitable plasticizers for the cellulose derivatives or resins are methyl phthallyl ethyl glycollate, dibutyl or dicyclohexyl phthalate, triphenyl or tricresyl phosphate, and methyl glycol ester of acetyl ricinoleic acid. In examples (1) a mixture of cotton fibres, waste rayon staple fibres, and fibres made of a copolymer of vinyl chloride and vinyl acetate is opened on a picker, carded twice, and the carded web built up into a multiply web or batt, which is sandwiched between non-adhesive sheets of textile fabric or waxed paper and pressed between a hot roller and a smooth stationary surface (2) a mixture of wool and waste cotton fibres is mixed in an air stream with fibres made from a mixture of cellulose acetate, polyvinyl acetate, and dibutyl phthalate, and the mixture falls on a perforated rotating hat mould. When a layer about an inch thick has been deposited, a co-operating heated mould is placed over the perforated mould and the fibrous layer hot-pressed to melt the thermoplastic fibres and bond the wool and cotton fibres into a hat. The products may be soft and fluffy, or dense, stiff, and resilient depending on the pressure and temperature employed. Specifications 541,888 and 547,288 also are referred to.